Dash-pot



1961 M. P. SCHOLZ 2,969,973

' DASH-POT Filed Sept. 21, 1959 INVENTOR.

Michael Peier Scholi .QJ-MA M ATTORNEYS DASH-POT Filed Sept. 21, 1959, Ser. No. 841,307

Claims. (Cl. 267-4) This invention relates to dash-pots and, more particularly, to a new and improved dash-pot construction particularly useful as an anti-stall device for delaying the final closing movement of a carburetor valve or throttle valve of an engine in order to prevent stalling of the engine. The dash-pot of the present invention is an improvement on that disclosed in my co-pending application, Serial No. 819,966, filed June 12, 1959 for Dash- Pot Device.

The dash-pot device of my co-pending application comprises a housing formed by two casing sections which serve to clamp between them an annular diagram, of rubber or rubber-like material, dividing the housing into two chambers. A fixture of non-magnetic material is clamped to the diaphragm around its central opening, and carries a ball valve of paramagnetic material cooperable with a valve seat. A stem is secured to the fixture and extends through one of the casing sections for engagement by a part of the operating mechanism of the carburetor or throttle valve to be controlled by the dashpot. Inwardly of this spindle, and immediately adjacent the valve seat, the fixture carries a permanent magnet which assists in maintaining the ball valve tightly seated against its seat.

During inward movement of the spindle, the valve is maintained against its seat and restricts passage of air between the two chambers, and thus retards the inward movement of the spindle. The spindle is embraced by a cup-shaped member of flexible material, such as natural or synthetic rubber, which serves to form a seal between the spindle and the casing. This cup-shaped member is, in turn, embraced by a cup-shaped coil spring which acts as a return spring moving the spindle in the outward direction. Such outward movement is substantially unrestricted as, during the outward movement, the air flowing through passages in the fixture forces the valve away from its seat so that there is fairly unrestricted flow of air between the two chambers. While this dash-pot device has proven very elfective in practical operation, it has been found that certain features thereof can be improved with improvement in the operation of the dash-pot.

More particularly, in the present dash-pot, the valve seat construction is simplified and reduced in cost, and the return, or outward movement, of the spindle, is effected by an enclosed coil spring which bears against a ball valve retainer, acting to limit outward movement of the ball valve from its seat, and against the head of a mounting screw for the dash-pot. Furthermore, one element of the valve seat assembly is eliminated by using one element to perform two functions. The exposed coil spring externally embracing the cup-shaped resilient member and exposed on the exterior surface of the dash-pot is also eliminated, and all of the operating parts of the dash-pot are enclosed. Thus the dash-pot components are less subject to any deterioration in their action due to foreign material and the like normally present around internal combustion engines.

For an understanding of the invention principles, refer- Ratented Jan. El, 1951 once is made to the following description of a typical embodiment thereto as illustrated in the accompanying drawings. In the drawings:

Fig. 1 is a plan view of a dash-pot embodying the invention;

Fig. 2 is a horizontal sectional view of the line 2-4 of Fig. 1; and

Fig. 3 is a sectional view of the line 33 of Fig. 2.

Referring to the drawings, the dash-pot includes a housing 10 formed by easing members 11 and 12 between which is clamped a flexible diaphragm 15 of rubber or any flexible and resilient rubber-like material, the diaphragm 15 being annular with circular inner and outer peripheries. For the purpose of clamping the diaphragm 15, casing members 11 and 12 are formed with flat peripheral flanges 13 and 1 1, respectively, lying in diametric planes, and the flange 14 of easing member 12 is bent over the flange 13 of casing member 11 to form a peripheraI lip 16 serving to clamp the flanges l3 and i4 tightly in engagement with opposite faces of the diaphragm 15. The casing members it and 12 may be made of any suitable material, such as a lightweight metal.

Casing member 11 has an integral tubular axial extension 17 formed with an inturned annular lip 18 which is engaged by the head 21 of a mounting screw 22 for the dash-pot and serves to retain screw or bolt 20 assembled to housing 10. For a purpose to be described, casing member 12 is formed with an axial opening having an inturned and rounded lip 22. Intermediate lip 22 and flange 14-, the external surface of easing member 12 is formed with a seat 23 for a purpose to be described.

The inner periphery of diaphragm 15 is clamped between the flat head 31, of a fixture 3d, and a washer 32 which has an L-shaped cross section. Fixture 30 is made of a suitable plastic composition material, such as nylon, and has an integral tubular extension 33 projecting from head 31 toward screw or bolt 2h. Washer 32 has a tight fit over tubular extension 33 or over an enlargement thereof at its junction with its head 31. A smaller diameter and relatively elongated tubular portion 34 extends integrally from the opposite surface of head 31 through the inturned annular lip 22. At the junction of extension 34 and head 31, a channel or plurality of apertures 35 are formed through the head 31. These apertures serve to establish communication between the chambers C and C into which the housing 10 is divided by the diaphragm 15 and its associated parts.

Extension 34 has a tight fit on a spindle 40 which extends outwardly beyond the outer end of extension 34. This spindle 40, which can be made of any suitable metal, is designated in the trade as a bumper stud. Spindle 40 has a reduced portion 41 which has the aforementioned tight fit within the extension 34, and has an outer extension with a substantially frusto-conical end 42. End 42 is arranged to be engaged by the rod associated with the control mechanism for the carburetor or throttle valve.

At the junctifion of the outer portion of spindle as with the reduced portion 4-1, the spindle is formed with a circumferential channel or groove 43 which receives the thickened inner margin 44 of a cup-shaped member 45 of rubber or other flexible and resilient rubber-like material. Member 45 has an outer periphery 46, also thickened, which bears against the seating surface 23 of easing section 12 and is held thereagainst by the resiliency of the member 45 to form a seal for the chamber C.

The tubular extension 33 contains the ball valve con trol mechanism. This ball valve control mechanism comprises a paramagnetic metal ball fs'tl cooperable with an annular valve seat member Sit of rigid nylon or other suitable diamagnetic material having a tight fit within the extension 33. Spaced from member 51 is a second annular member 52 of the same material and also having a tight fit within the extension 33. The opening in member 52 is somewhat larger than the ball Stl, and member 52 has an inturned lip 53 which serves to limit outward movement of ball 50. A permanent magnet 55 is seated within the inner end of extension 341, having a tight drive fit therein, and serves to attract ball 5t) into closing engagement with valve seat 51. Magnet 55 is so designed that it does not interfere with the channel or passages 35.

In accordance with the invention, a coil spring 69 is seated against the ball retaining member 52 and the head 21 of bolt or screw 28. This coil spring 60 normally biases the device to a position in which plunger or spindle is projected to the full extent permitted by diaphragm 15.

The dash-pot operates as follows. Upon closure of the carburetor or throttle valve, the afore-mentioned rod moves the spindle 40 inwardly. However, such inward movement is retarded by virtue of the fact that magnet 55 attracts ball into closing relation with seat 51, so that air can pass only in a restricted manner from cham ber C to chamber C. The seating of ball 50 against valve seat 51 is assisted by the air pressure within the chamber C. There is, however, suificient leakage of air around the ball 50 so that air will flow slowly from chamber C into chamber C but only at such a rate that inward movement of the spindle 4-9, and thus closing movement of the carburetor or throttle valve, is retarded or delayed.

Upon reopening of the carburetor or throttle valve, the spindle 40 is released by the bar R and the spring 60 rapidly moves the plunger or spindle 4i} to its outermost position. During this movement, the air flowing from chamber C toward chamber C through passages 35 tends to move valve 50 away from valve seat 51 and thereby to provide for relatively unrestricted flow of the air from chamber C to chamber C. Hence, the return movement of the spindle is rapid and relatively unrestricted.

It should be noted that extension 33 is preferably so designed that it has a guided but freely movable fit in the extension 17. Also, as compared with the dash-pot device of my said co-pending application, only valve seat 51 and valve retainer 52 are provided, thus eliminating the separate valve retaining member of my said co-pending application. All of the parts, including the return spring 60, are fully enclosed so that there is little if any danger of foreign material afiecting the operation of the dash-pot.

While a specific embodiment of the invention has been shown in detail to illustrate the application of the inven- 0 tion principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A dash-pot comprising, in combination, means forming a housing; diaphragm means, including an an nular flexible diaphragm dividing said housing into a pair of chambers; an operator extending slidably through a wall of said housing and perpendicular to and engaged with said diaphragm means, said operator extending through one of said chambers; diamagnetic material means, including a valve seat, included in said diaphragm means and establishing communication between said chambers; 21 paramagnetic material ball check valve in the other of said chambers cooperable with said valve 6 seat to restrict communication between said chambers; a magnet movable with said operator and normally retaining said valve against said valve seat to ,so restrict communication between said chambers; said valve, upon movement of said operator in the direction of said valve, being retained seated against said valve seat by the action of said magnet augmented by the resultant relatively increased pressure in said other chamber, to retard such movement of said operator; said valve, upon reverse movement of said operator, disengaging said seat by virtue of the resultant relative increase in pressure in said one chamber opposing the action of the magnet to facilitate such reverse movement of said operator; and coil spring means, within said housing, operatively associated with said diamagnetic means and biasing said operator to move in such reverse direction.

2. A dash-pot comprising, in combination, means forming a housing; a flexible diaphragm dividing said housing into a pair of chambers; a diamagnetic fitting secured to the central portion of said diaphragm and having a fiat surface portion overlying one surface of said diaphragm and a tubular extension projecting from the other surface of said diaphragm; means, including a diamagnetic valve seat in said tubular extension, establishing communication between said chambers; a paramagnetic material ball check valve cooperable with said valve seat to restrict communication between said chambers; an operating member secured to said fitting and extending slidably through a wall of said casing substantially perpendicular to such one surface of said diaphragm; a magnet carried by said fitting and effective to attract said valve to seat against said valve seat; a coil spring engaged between said tubular extension and a wall of said housing and biasing said operator outwardly of said housing; said valve, upon inward movement of said operator, being retained seated against said valve seat by the action of said magnet augmented by the resultant relative increase in pressure in one of said chambers to retard such movement of said operator; said valve, upon outward movement of said operator under the influence of said coil spring, disengaging said seat by virtue of the resultant relative increase in pressure in the other chamber opposing the action of said magnet, to facilitate outward movement of said operator.

3. A dash-pot device as claimed in claim 2 including an annular valve retaining member of diamagnetic material spaced from said valve seat and limiting movement of said valve away from said valve seat; said coil spring engaging said valve retaining member.

4. A dash-pot as claimed in claim 2 in which said housing has an aperture aligned with said operator and in the opposite wall of said housing; a mounting bolt extending through said aperture and having a head lying within said housing; said coil spring engaging the head of said mounting bolt.

5. A dash-pot as claimed in claim 1 including a cupshaped member of flexible and resilient material having an aperture in its base receiving, in sealing relation, a portion of said operator outside said housing, and having its rim engaged in sealing relation with said housing; said cup-shaped member preventing entry of air, dust, or the like into said housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,597,952 Rosenlund May 27, 1952 2,732,038 Olson et al. Jan. 24, 1956 2,894,740 Emerson et a1 July 14, 1959 FOREIGN PATENTS 744,858 Great Britain Feb. 15, 1956 

